Investigating life-cycle cost for resilient RC frames with enhanced seismic performance objectives

A seismic-resistant structure not only should provide safety for the residents but also it should minimize the financial loss resulting from the earthquake. Therefore, it must be demonstrated that the structure will remain in acceptable situation after the earthquakes with various intensities. The past has shown that, the financial loss of earthquake for the structures that have been designed based on performance objectives of current seismic codes, is considerable and this results in additional problems. Therefore, it seems that upgrading performance objectives for structures can significantly reduce earthquake losses. Improving the performance objectives of structures is associated with increasing the initial cost of the project. But reducing the damage of resilient structures and the cost of repairing of damaged components in these structures can reduce the ratio of initial cost to total cost.In this study, the effect of enhanced performance objectives in increasing the initial cost of the project and reducing the costs of repairing the damaged components of concrete structures is discussed. To investigate this issue, 3, 5, 10 and 15 storey regular concrete frame structures are modeled and designed based on Design Basis Earthquake of current seismic codes (DBE) and also based on Maximum Considered Earthquake (MCE) for the same performance objectives. The loss and repairing cost of the structures are evaluated according to FEMA-P58 guideline and using PACT software under 6 near-field and 5 far-field records. The results of this study show that, enhancing the design objective of concrete frame structures increases initial cost of lateral resisting frames (beams and columns) and the total cost of the building by 23% and 5%, respectively. Whereas the repair costs of the structure and the whole building are reduced by 43% and 18%, respectively, which ultimately leads to reduction of the life cycle cost for the structures by 13%.